Conventionally, as a method for obtaining an ester compound, a method (a method utilizing so-called the oxidative alkoxycarbonylation reaction (esterification reaction)) has been known in which a norbornene-based compound having a carbon-carbon double bond is reacted with an alcohol and carbon monoxide by using a palladium catalyst to thereby introduce (add) ester groups to the carbon atoms forming the double bond and obtain an ester compound.
For example, International Publication No. WO 2011/099518 (PTL 1) discloses a method in which a norbornene is reacted with an alcohol and carbon monoxide by using a palladium catalyst and an oxidizing agent to thereby introduce ester groups to the carbon atoms forming the carbon-carbon double bond (olefinic double bond) in the norbornene and obtain an ester compound. PTL 1 discloses that palladium catalysts usable in the method include palladium chloride, palladium nitrate, palladium sulfate, palladium acetate, palladium propionate, palladium carbon, palladium alumina, palladium black, and the like.
Meanwhile, Japanese Unexamined Patent Application Publication No. Hei 7-173107 (PTL 2) discloses a method in which a norbornene such as norbornadiene, dicyclopentadiene, or bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride is reacted with an alcohol, carbon monoxide, and oxygen in the presence of a catalyst comprising (1) palladium metal or a compound thereof, (2) a copper compound, (3) a chlorine compound, and (4) a manganese or zinc compound to thereby introduce two carboxylic acid ester groups per carbon-carbon double bond contained in the bicyclo[2.2.1] ring of the norbornene. PTL 2 discloses that palladium metal and compounds thereof usable in this method include: materials in which palladium metal is supported on a support such as activated carbon, silica gel, alumina, silica-alumina, diatomite, magnesia, pumice, or molecular sieve; palladium metal such as palladium black; zero-valent palladium complexes such as palladium dibenzylideneacetone complex and tetrakis(triphenylphosphine)palladium; divalent palladium compounds including palladium halides such as palladium chloride and palladium bromide, inorganic acid salts of palladium such as palladium sulfate, palladium phosphate, and palladium nitrate, organic acid salts of palladium such as palladium acetate, palladium propionate, and palladium benzoate, palladium complexes such as bis(acetylacetonate)palladium, dichloro(cyclooctadiene)palladium, palladium chloride benzonitrile complex, and palladium chloride ammine complex; and the like.